A woman who murdered five members of a family, including three young children, when she set fire to her neighbour's pushchair, has been jailed for at least 30 years.

Alcoholic Melanie Smith, 43, started the devastating blaze because she was angry the pushchair had been left in a shared hallway close to the front door of her flat.

Lee-Anna Shiers, 20, her four-year-old nephew, Bailey, and two-year-old niece, Skye, were trapped in their upstairs flat and died in the arson attack in north Wales on 19 October last year.

Firefighters managed to rescue Shiers's 15-month-old son, Charlie, and his father, Liam Timbrell, 23, but they died in hospital.

Smith, who lived in the flat below the victims in Maes y Groes, Prestatyn, was found guilty of five counts of murder and one count of making threats of arson by a jury at Mold crown court last Tuesday.

Smith wept as the sentence was passed by the trial judge, Mr Justice Griffith-Williams.

He told Smith that at first it seemed unlikely that a mother-of-five with no previous convictions could set fire to a house with people in it. But after hearing the evidence, he said he was satisfied that Smith set fire to the pushchair.

He said Smith was motivated by jealousy due to her faltering relationship with Stephen Clarkson, whom she accused of cheating on her with a woman called Samantha Schofield – a woman she hated.

"That hatred, which was all the more intense because of your drink problem, took over your life," the judge said.

Smith was convicted after the jury of seven women and five men reached 10-2 majority verdicts following 15 hours of deliberations.

Smith had been increasingly angry with Shiers, accusing the young mother of being a noisy and untidy neighbour, her trial was told.

Witnesses said Smith had been heard complaining about Shiers leaving the pram in the hallway and leaving cigarette ends around the front door area.

On the night of the fire, Smith was drunk and started the blaze "in a rage" after hearing Shiers and Timbrell having sex upstairs, it was said.

The court was played a harrowing 999 call in which Mr Timbrell shouted: "Oh my God, oh my God, we're going to die."

The jury was told that Timbrell later told rescuing paramedics that "it was arson" and "it was Mel" and said he heard Smith shouting through the letterbox that she was going to burn the house down.

The judge said that while her relationship with Clarkson remained "uneasy" Smith took out her unhappiness on Shiers. "And she became the focus of your attentions," he said.

The court heard that Smith was a "very tidy person". "You resented any mess she made," Griffith-Williams said.

The inconvenience of the pushchair in the hallway, cigarette ends dropped by the front door, and noise coming from upstairs all became "issues which grew out of all proportion".

The judge said that, on that Friday evening, Clarkson wanted little to do with the defendant. Smith, who, the judge said, was "certainly affected by alcohol", purchased a takeaway to eat alone at home.

The judge told her: "My belief is that at that moment you were probably a very sad woman and it was the sound of Lee-Anna and Liam's love-making from the flat above that overwhelmed you.

"Bitterly resentful of their happiness, you went outside and set fire to the pushchair. It follows that you acted on impulse and so this was not a premeditated act.

"My belief is you did not know Bailey and Skye were there but that reduces your culpability only marginally because you were clearly indifferent to the presence of others in the flat upstairs.

"The setting-fire to the pushchair was an act of exceptional wickedness, almost unparalleled in its consequences.

"For those who had to hear the evidence of the 999 calls, the horror of those moments in the flat upstairs as Lee-Anna and Liam faced the awful inevitability of their imminent deaths will be forever etched on their memories.

"Understandably the knowledge of the manner of their deaths has added to the overwhelming grief of their families, all the more to those who rushed to the house in the hope they could help.

"I have had regard to the contents of the three victim statements. Each witness wrote eloquently of the effects upon them and their families of their losses.

"That grief will not have been mitigated by any meaningful remorse on your part. You continue to portray yourself as a victim, blinding yourself to the sufferings of the real victims in this case and failing to at least acknowledge that it was your deliberate act which started the fire."